1. Field of the Invention
The present invention relates to an automatic power brake system for an automotive vehicle. More particularly, it relates to an automatic emergency brake system for an automotive vehicle which goes into action without being controlled by a driver in the event of a collision and prevents additional accidents after the collision, thus assuring safety of passengers.
2. Discussion of Related Art
A hydraulic brake system for an automotive vehicle has an assistor for doubling manipulated variable utilizing intake negative pressure of a vehicle engine generated during running.
Referring to FIG. 1, a sectional view of main parts of a conventional hydraulic power brake system, the conventional hydraulic power brake system for an automotive vehicle includes a master cylinder 1; and an assistor 2 provided to master cylinder 1 for augmenting the force applied by an operator, and having a power cylinder 3, a power piston 5 installed in power cylinder 3 supported by a return spring 4, a forward push rod 6 connecting the forepart of power piston 5 with a piston 1-2 of master cylinder 1, and a backward push rod 8 supported by a return spring 7 and connecting the rear of power piston 5 with a brake pedal (not shown).
As a driver pushes down the brake pedal with his or her food to make the vehicle slow down or stop, backward push rod 8 is pushed to operate power piston 5 of assistor 2. Forward push rod 6 of assistor 2 pushes master cylinder 1 so that a brake fluid is furnished to a wheel cylinder, thus making the vehicle stop.
An automotive vehicle equipped with such a conventional hydraulic power brake system does not stop until its driver pushes down the brake pedal with his foot. In the event of a collision, if a driver fails to brake his or her car with an automatic transmission, which is in speed change mode as running mode, the car keeps going straight ahead without the driver's manipulating its accelerator, thus causing additional accidents. In case of an emergency such as a collision, when the driver fails to put on the brake and his or her car must be braked urgently, the conventional hydraulic power brake system cannot reduce or prevent accidents.